The contraceptive Pill and cancer – a look behind today’s headlines

Women taking the Pill may have been alarmed by headlinestoday linking the oral contraceptive with breast cancer. But for women thinking of chucking their packet in the bin, it might reassure you to know that we don’t advise against taking the Pill – even though we agree that it slightly raises the risk of breast cancer.

That’s because, on balance, the Pill prevents more cases of cancer than it causes. On top of this, there are lots of other things to consider when deciding if the Pill is the right choice for you. It isn’t just about cancer, and nor should it be. While much of today’s news focuses on Pills containing higher levels of the hormone oestrogen, the study in question didn’t conclusively show they led to a higher risk.

It’s a complicated business, and stories like this one don’t always put new results into context, so let’s take a brief look at the bigger picture and what today’s study really shows about higher oestrogen Pills.

The Pill and different types of cancer

There are lots of important aspects to consider when it comes to the Pill and cancer, but the main thing is that it reduces the risk of some cancers and increases the risk of others. We’ve written about this before, but the main effects are:

Reduced risk of womb and ovarian cancers, which lasts for decades

Increased risk of breast and cervical cancers, which goes away within about 10 years of stopping the Pill

Because the risk of cancer increases with age, the timing of these effects plays an important role in the number of cancers caused and prevented by the Pill.

Women take the Pill when they’re younger, so although they have a temporarily increased risk of breast and cervical cancers it’s when their underlying risk is low. To put it another way, a modest increase in a small risk is still a small risk, so the overall or absolute risk remains low. Our scientists have actually calculated that each year the Pill causes around 850 cases of breast and cervical cancers.

On the other hand, the lasting protection against womb and ovarian cancers continues as women get older and their underlying risk of these of these types of cancer increases. Around 1,400 womb cancers and 600 ovarian cancers are prevented by the Pill each year.

So overall, the evidence tells us that the Pill prevents more cases of cancer than it causes.

Different formulations of Pill

There are two main types of Pill:

The combined Pill, containing sources of oestrogen and another hormone called progesterone, is the most common type.

The progesterone-only Pill, also known as the mini-Pill or POP, is less popular. Although the evidence is less clear, the POP seems to affect cancer risk in the same way as the combined Pill.

Today’s study looked at different formulations of the combined Pill. Over the years this has changed in various ways, but in particular the oestrogen dose has tended to get lower. So there’s a question about whether newer, lower oestrogen formulations affect the risk of different cancers in the same ways as older versions.

The International Agency for Research on Cancer (IARC) is an organisation that evaluates the risk of cancer from various things in our environment (more here). Its latest look at the evidence on the combined Pill and cancer found that there wasn’t enough evidence to say whether or not different formulations of the Pill have a similar effect on the risk of breast cancer. But they did note there was evidence suggesting that lower-oestrogen formulations might offer even better protection against ovarian cancer.

The new study doesn’t show that higher oestrogen pills are riskier

The study published today in the journal Cancer Research set out to investigate the relationship between different formulations of Pill and breast cancer. They relied on the fact that, in the US, people often have health insurance – and insurance companies keep detailed information about what drugs people take at different points in their lives, and what diseases they subsequently develop.

The study looked at two groups of women, those who took the Pill in the year before they were diagnosed with breast cancer, and those who didn’t.

Yet despite the media coverage about high oestrogen Pills being riskier, on the whole the researchers showed that the different types of Pill had pretty similar effects on the risk of breast cancer. Commenting on their results the authors say they only found one formulation that was ‘significantly different’ from the others – all the other results were likely to be explained by chance (in technical terms, they weren’t ‘statistically significant’) – including the finding about Pills containing high levels of oestrogen.

The advantage of their approach is that they used accurate information on exactly which type of Pill women were taking, directly from their prescription records. This helps to get around the problem that women may not accurately remember exactly which Pill they were taking at what period in their lives – this can make studies inaccurate or mean that they simply don’t have enough reliable information to find answers.

But there were problems with how the study was carried out

It’s important to point out that this study did have several problems that mean we can’t rely on its results. It didn’t fully take things like age or family history of breast cancer into account, nor whether women had recently had breast screening. But, more importantly, it doesn’t take account of women’s previous use of the Pill.

The second group of women – those who didn’t take the Pill in the year before their breast cancer diagnosis – includes both women who have never used the Pill and women who used the Pill previously. We don’t know about past Pill use in any of the women – and this could make an important difference, because we don’t know what types of Pill the women used in the past. Or in the case of former users, how long ago they stopped taking the Pill, which would affect their current risk of breast cancer. On top of this, women who’ve used the Pill for longer are, logically, more likely to be using older formulations.

But the study does make some interesting early observations worthy of further research, such as that relatively recent, low oestrogen Pills could have a weaker or even no effect on the risk of breast cancer – but we’d need to see some longer term better quality research, looking at their use over long periods of time to draw any firm conclusions on this. And it would also be important to check what the effects on other types of cancer were.

So what is our advice on the Pill?

This study doesn’t change our view on the Pill, and it certainly isn’t grounds to recommend women stop taking it, or switch to a different type.

If you’re worried about the Pill, for any reason, or if you’re wondering about whether to start or stop taking it, speak to your GP or local family planning service. As well as being able to give you advice more specific to your own circumstances, they can also discuss alternative options with you.

We don’t advise women to avoid taking the Pill, and we don’t suggest that they should take it either. When it comes to cancer, the Pill has pros and cons and we think that women should have clear information about this along with the other benefits and risks. But at that point, we take a step back – armed with the information, women can make their own choice about what’s right for them.

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cerelle pill switching to micronor?
i was on the cerelle pill mini pill for around 4 month but it was making me depressed and i was insane, lashing out and crying my eyes out wanting to die for the most pathetic reasons ever usually arguments with my boyfriend. i was never like this before but i have an awful violent side to me now i cant help. everything else about this pill is great. it has stopped my periods which is good for me and i have had no other side affects such as acne or weight gain, i have decided t change to micronor help my mood swings. can anybody tell me if this will still stop my periods or how it will affect me (in likelihood) and if it well get rid f these awful mood swings

Remember the words of German philosopher Arthur Schopenhauer who, 200 years ago, said all truth goes through three stages:
•First it is ridiculed
•Then it is violently opposed
•Finally it is widely accepted as self evident

So pleased to read this . I had leaukaemia age 39 so early menopause. I have no history of breast cancer in my family but great grandma was Jewish so I am concerned about ovarian cancer. I have written at length to my GP stating my case but he wants to take me off mycrogynon as I am now 55. I am considering buying them from the internet if he will not prescribe them as I feel so strongly about the benefits on cardio and imune system. Unfortunately the GP just reads the BNF which quotes age 50 but my circumstances are not the norm. I have contacted the pill manufacturer direct but they just refer me to the GP. Any info you have to back my case would be appreciated.

I found this very interesting and good to talk with my daughter, especially as cancer has affected my family, with my mother dying of cervical cancer and my mother in law surviving breast cancer it just helps , thankyou.

I had polycistic ovary syndrome which the combined pill helped but I decided to have the meriner coil fitted. From day 1 my pcos flared and my weight went up out of control. I had it removed and a few months later I had an aggressive cancer 2009…. lumpectomy radiotherapy chemotherapy and herceptin with tamoxifen. In 2012 I had another breast cancer non aggressive so lumpectomy radiotherapy and a prospect of having my ovaries chemically shut down for 5 years. I opted for an oophorectomy. I think the coil was to blame.

My friend died age 19 she was on the pill, I went to see my gp concerned about taking the pill and was told that it was not a risk, I wanted to be sterilised and kept going back to my gp asking to be referred to be sterilised and she kept defusing, I was then diagnosed with a grade 3 breast cancer which has spread into my lymph glads. HER 2 + chemo radio herceptin 4 operations and a hysterectomy. Thanks Doc.

I was diagnosed with breast cancer in 2010 which was oestrogen fed.
I had a lumpectomy, hysterectomy, chemotherapy, radiotherapy and a year of herceptin and am still on daily aremidex. I also had the mirena coil fitted for many years, before diagnosis.
I have 2 teenage daughters and find it a worry when thinking about which contraception is best for them.
This article has helped.

I was diagnosed with oestrogen positive breast cancer and had the breast removed in January of this year. I had never taken the pill for any long periods of time as it didn’t suit me but 7 years ago I started using the Mirena coil which is progesterone based I believe. When I was diagnosed by cancer team advised me to have it removed as the research into progesterone’s relationship with oestrogen was unclear so I did to be on the safe side. I cannot say if this caused my cancer but it is high on my list of suspicions.

In 1973 my mother, who was then 36 years old was diagnosed with breast cancer and subsequently had her breast removed. At the time, she was told that it was due to the hormones in the pill that had caused the cancer and was advised to not let any daughters she may have take the pill. I cannot speak for my sister but, I personally have never taken the pill and have advised my own daughter not to. I am pleased to say my mother lived another 40 years after having had her breast removed and recently died at the age of 77 years, which was not cancer related.

I took the contraceptive pill for many years and stopped it after a nurse on my pill check said why am I taking it,,,its not a vitamin!!!! i stopped in January 2010 and was diagnosed with Oestregen related breast cancer. This was probably a coincidence and i havent dwelled on this as there are many factors to the possible cause. This is a good article tho, thank you.

I was put on the pill after the birth of my first child as my period pain was the equivalent to the 1st 2 stages of a birth.any risk was worth being pain free to me.I’m now 74 so no harm done as far as i know

A very good article. As a GP (now retired) I remember a lecture on the Pill and a slide showing numerous studies of the effect on breast cancer incidence. They were all except one a little either side of no effect except one, which showed a greatly increased risk, examination of which, showed a flawed study. Apart from the protective element for ovarian and endometrial Ca, it is easy to forget that an unwanted pregnancy can carry more risk.

Thanks for this article – really informative and helpful and should be shared far and wide!
I hate how the press sensationalises everything, leading to misinformation and panic. Good to see something a bit more sensible from real experts. Thanks!

I took the pill for probably 15 years, then had a hysterectomy at age 40 due to endometriosis. I am now 68 and 3 years ago had surgery for breast cancer had the cancer removed and up to press it has not returned. As you say in the tests it has been a long time since I took the contraception pill, and therefore probably had no influence on the cancer.

I have been on the depo-provera twice, and I am glad I came away from it. My Mum and my Nan have both had hormone related breast cancers. My Mum had a coil fitted for many years and was advised to get it removed once her treatment was finished. After speaking to a consultant at my local hospital, she advised I had made the right decision to come off of the depo.

Does taking the pill for many years cause scarring on the liver?
I am now 71 but I took the pill from the age of 45 until into my 60’s.
I was told that this had probably left a scarring mark seen on my liver during MRI scans.

Candi – sorry to hear about your mini stroke. I don’t think you can assume the two are linked it just appears that the timing of these events was unfortunate. Genetics/family history and lifestyle ie smoking are significantly related to this predisposition.
University lecturer Amanda

Very interesting breakdown. I have wondered whether there are genetic associations to risk with the pill, or raising estrogen levels – but it sounds like this study doesn’t go near that area. Reading your limitations within this study, those are some rather significant areas, for sure. It’s too bad they weren’t factored in. Hopefully they will be in the future. ~Catherine

The pill is a joke I took it for 6 weeks and ended up having a mini stroke due to a blood clot that formed in my head I’m now on medication for 6 months and I’m only 30 this stuff doesn’t run in my family and I’m a healthy person

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